1. Field of the Invention
The present invention relates to electrical connectors and, more particularly, to an electrical connector wherein a pair of support plates are relatively moved to bring the male contact elements into contact with the female contact elements.
2. Description of the Related Art
An example of such conventional electrical connectors is disclosed in U.S. Pat. No. 5,707,247.
As shown in FIG. 4, male and female contact elements 51 and 61 are supported at regular intervals by first plate 50, such as an IC package, and second support plate 6O, respectively. Each male contact element 51 has a pin-like form and extending downwardly from the first support plate 50 and passes through an aperture 53 formed in an intermediate plate 52. Each female contact element 61 has narrow and wide sections 61A and 61B, respectively, and placed in a window 62 of the second support plate 60.
The intermediate plate 52 is provided with an elongated hole 54, and the second support plate 60 has a bearing hole 63 in which an eccentric cam or driving shaft 70 is fitted for rotation. The driving shaft 70 has a shaft section 71 supported by the bearing hole 63 for rotation, a driving section 72 situated in the elongated hole 54, and a flange section 73 situated above the driving section 72. The driving section 72 has a generally cylindrical surface which is eccentric relative to the shaft section 71 and has a diameter larger than that of the shaft section 71. The driving section 72 is provided with a flat portion 72A to form a gap (d) between the driving section 72 and the elongated hole 54 in the direction of minor diameter of the elongated hole 54. A groove 73A is provided in the top of the flange section 73 to receive a screwdriver or the like to produce a torque.
In operation, as shown in FIGS. 5(A)-(C), when the driving shaft 70 is turned clockwise by a predetermined angle from FIG. 5(A) to FIG. 5(B) to move both of the intermediate and first support plates 52 and 50 relative to the second support plate 60 by a difference (Rxe2x80x94r), wherein the R and r are the largest and smallest radii, respectively, of the driving section 72 from the axis of the shaft section 71, pushing the male contact elements 51 into the narrow sections 61A of the female contact elements 61 under contact pressures, thus providing connection between the contact elements.
When the driving section 72 is moved from FIG. (B) to FIG. (C), the flat portion 72A is opposed to a major wall of the elongated hole 54, forming the gap (d). Consequently, the necessary torque for rotation abruptly becomes zero at the connection position as shown in FIG. 5(C), providing the operator with a sense of a click indicating the connection. The gap (d), however, forms a play and changes the contact pressure under the influence of an impact or vibration. As a result, not only the contact resistance of contact elements becomes unstable, but also the position of the eccentric cam is difficult to control.
Accordingly, it is an object of the invention to provide an electrical connector capable of not only providing a sense of click upon connection of the contact elements but also making the connection kept stable.
According to the invention there is provided an electrical connector for connecting a first support plate having at least one male contact element, a second support plate having at least one female contact element, and a drive mechanism for moving the first support plate relative to the second support plate in a first direction between a lock position where the male contact element is brought into contact with the female contact element and a release position where the male contact element is disengaged from the female contact element.
The drive mechanism comprises a bearing hole provided in either of the intermediate or first plate and the second support plate; an elongated hole provided in the other member and extending in a second direction perpendicular to the first direction; and a driving shaft having a shaft section in sliding relation to the bearing hole and a driving section provided in the elongated hole and having a small-diameter portion, a large-diameter portion, and a pair of transitional portions between them. The elongated hole has a minor diameter substantially equal to a sum of radii of the small- and large diameter portions and a major diameter greater than the minor diameter so that when the driving shaft is rotated, the large-diameter or transitional portion engages a major side of the elongated hole to bring the first plate to the lock position or disengages the major side to bring the first plate to the release position.
The spring contact between the contact elements may be made by the large-diameter portion pushing the minor diameter side of the elongated hole. Since the large-diameter portion has a constant radius, there is no play produced and a sense of click is generated when the pushing point moves from the transitional portion to the large-diameter portion. However, a small torque is generated by the reactive force due to the spring contact between the contact elements, making the position stable. The large-diameter and transitional portions may have bottom faces in sliding relation to the second support plate so that rotation of the driving shaft is made smooth. The bottom faces and the second support may be provided with stoppers to prevent the driving shaft from being rotated beyond the connection position. The first support plate may be part of an integrated circuit package.